A completely safe, inert contrast material (CM) for angiomyelo-, and cisternography has not yet been developed. Oral cholecystopaques do not have a reliable, high target organ affinity. Toxicity of current CM is presumed due to hydrophobicity, charge, and hypertonicity of their solutions. Earlier research by this group established the correlation between hydrophobicity, toxicity, and interaction with proteins. Based on this work, we developed a design concept of improved CM. Pilot compounds with potential in both areas were synthesized and tested: High water solubility and 1ox toxicity was achieved in nonionic compounds triglucosyl-diiodobenzene (i.v. LD 50 - 34g/kg bw, mice) and 2,4,6, triiodo-3-acetamido-5-N-methylcarboxamidophenyl -D-glucopyranoside (i.v. LD 50 - 24.5g/kg bw, mice). Excretion in bile was achieved with glycosyl iopanoate ester, tetraiododiphenolsulfone and iodoclovoborates. We propose: (A) for cardiovascular or intrathecal applications to synthesize highly hydrophilic, nonionic, water-soluble and stable iodobenzene derivative substituted with polyhydroxyls, i.e. carbohydrates attached via acetals, ethers, or amine bonds for stability and reduced toxicity; and to link such monomers into oligomers using reduced peptides to lower hypertonicity of the solutions. (B) for oral cholecystrography, to explore the effects of attaching to the source of opacity a moiety which would increase its resorption from the gut, to synthesize: 1) derivatives of iodoclovoborates B12InH10-n (COOH)2 with detoxifying substituents; 2) conjugates of bile acids with derivatives of triiodobenzoic acid; 3) oligomers of triiodophenyls based on derivatized reduced peptides. All new compounds will be characterized chemically. Compounds with potential for radiography will be systematically tested by their effects on enzymes, excretion patterns and dynamics, i.v. and oral lethal doses in several species, and their effects on function and morphology of target organs.